Pressure testing a "Watchco" SM300

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We do a lot of pressure testing of industrial systems and use a digital pressure gauge. The beauty of it is that we don't have to worry about the full range scale being too high or low for the system pressure we are testing. The digital gauges use piezoelectric crystals, so they are accurate along the full range (0 - 5000psi in our case). If it matters to you, the cost is pretty low ($300 or $400 US).

From what I see though, if I were you, I would not bother with the digital.

Thanks for posting. The geek in me loves this stuff.
 
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duc duc
We do a lot of pressure testing of industrial systems and use a digital pressure gauge. The beauty of it is that we don't have to worry about the full range scale being too high or low for the system pressure we are testing. The digital gauges use piezoelectric crystals, so they are accurate along the full range (0 - 5000psi in our case). If it matters to you, the cost is pretty low ($300 or $400 US).

From what I see though, if I were you, I would not bother with the digital.

Thanks for posting. The geek in me loves this stuff.

Thanks, and glad you enjoyed it.

I used to be an engineer (still am I guess, just have a different day job), and have bought hundreds of pressure gauges in my 23 years doing that, so yes I understand how all this works and what's available on the market. And I agree, anything more accurate is just not warranted for this application. As noted, the unit I use is specifically approved by Omega, so if they aren't concerned about this, neither am I. There's plenty of safety factor built into the watches and the test procedures to cover gauge errors.

Compared to the systems I used to design and work on, this is very crude work.

Cheers, Al
 
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I'm guessing here, but I think this might apply to you (not my photo BTW):

 
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Does anyone know why Omega called it the Seamaster 300 when it was only rated to 200 meters?
 
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For my buddy Stas...and anyone else who may be interested, even though they don't dive...

I didn't want to post anything until I found these photos...but I knew I had tested at least one of these before, so after some digging, here you go. I'll start off by stating this is the second time the case was tested, because all of what you will see here is done with the case empty first, in case there is a failure. Then once the empty case passes, the movement is installed, and the test is repeated, so this is that second test. Start by using the dry testing machine, set to the dive watch program - it will use a -0.7 bar vacuum, and then a +10 bar pressure to test the watch, while carefully measuring the deflection of the case:



The watch passes both tests:



Now off to another room where the high pressure wet testing equipment is located:



The watch is placed in the testing chamber, and the chamber is filled with water:



The chamber is closed, and the watch is left with no additional pressure applied for 30 minutes - note that I hadn't wound the watch, so it wasn't running:



After 30 minutes the pressure is increased. This particular equipment is capable of testing to 125 Bar, but that is for very rigid dive watches with thick sapphire crystals. In this case I used 25 Bar, so 200 m rated depth +25% safety margin as per Omega standards for this kind of testing of their proper dive watches - here is the pressure gauge:



Shot of the watch in the chamber and you can see the pressure gauge also:



I leave it at this pressure for one hour, then lower the pressure back down to zero, and leave it in the chamber for another 30 minutes:



The watch is then removed from the testing chamber:



Placed on a heating plate that will bring the temperature of the watch to 47 degrees C - this takes 30 minutes:



After 30 minutes have elapsed, a drop of cool water is placed on the crystal, and left for one minute:



It is then wiped away, and the crystal is examined under a loupe to ensure that no condensation has formed on the underside - seeing none, the watch has passed:



et voilà

Cheers, Al
Wow! Thank you do much


Sent from my iPhone using Tapatalk
 
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you use cheap manometer with 63mm diameter which questionable precision... didn't expect this in watch testing equipment.
See, here I was thinking a "manometer" measured how much of a man Al was!
 
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duc duc
I'm guessing here, but I think this might apply to you (not my photo BTW):


I need that shirt - then I can wear it when one of my "artsy" friends come over wearing his favourite shirt...



👍
 
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@Archer this may sound like an odd question but have you ever / often for curiosity sake pushed a case beyond its limits intentional to failure to see when / where that failure occurs? Like taking a sealed but empty SM300 and going above the 25%, and continuing until either the crystal caseback or crown finally goes pop?
 
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@Archer this may sound like an odd question but have you ever / often for curiosity sake pushed a case beyond its limits intentional to failure to see when / where that failure occurs? Like taking a sealed but empty SM300 and going above the 25%, and continuing until either the crystal caseback or crown finally goes pop?

Probably a lot more cost effective to do it with a Seiko...
 
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Wow this is very impressive. I always wondered how this testing was done. Thanks @Archer you're such an asset to this forum.
 
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@Archer this may sound like an odd question but have you ever / often for curiosity sake pushed a case beyond its limits intentional to failure to see when / where that failure occurs? Like taking a sealed but empty SM300 and going above the 25%, and continuing until either the crystal caseback or crown finally goes pop?

Yes...that is an odd question. Any time you want to provide a case for testing, I will perform the test and thoroughly document the results for the forum. 😀
 
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Yes...that is an odd question. Any time you want to provide a case for testing, I will perform the test and thoroughly document the results for the forum. 😀
That was actually going to be my next question, what would be a representative case to use... We might take you up on that some time if you'd be willing to video the results, it'd be pretty cool to see.
 
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That was actually going to be my next question, what would be a representative case to use... We might take you up on that some time if you'd be willing to video the results, it'd be pretty cool to see.

Representative of what - testing a SM300? Not sure I can think of a good analog off the top of my head...

I am certainly willing to do the test and take a video of it....
 
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I guess from my perspective I wouldn't mind seeing just how far a Seiko SKX007 could be pushed - but I don't have a donor one ;-)
 
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Al - IIRC, when you pressure tested the SM300 you built for me, I believe I recall (and I may be wrong) that you saw some deflection in the crystal or caseback that cause the second hand to stop, but that there was no water infiltration. I seem to recall you saying that you had seen that one other time but that it did not affect the pressure test or the operation of the watch under normal parameters. Does that sound correct?
 
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Thanks for this Archer.
Was the test made on a watchco made in Oz/NZ or one you put together yourself ?
I ask because I'll be picking up my Oz/NZ made version next month and this was the first test I wanted done as soon as I picked it up. I now wonder if it needs it. I wont be diving but it will certainly get wet swimming and hopefully kayaking.
 
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All these use the same cases, so who assembles it should not matter. I would ask the vendor if they have pressure tested it, how they did it, and to what pressure(s) they tested it to...

I would at least want a test in a dry testing machine to verify it was assembled correctly.
 
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Al - IIRC, when you pressure tested the SM300 you built for me, I believe I recall (and I may be wrong) that you saw some deflection in the crystal or caseback that cause the second hand to stop, but that there was no water infiltration. I seem to recall you saying that you had seen that one other time but that it did not affect the pressure test or the operation of the watch under normal parameters. Does that sound correct?

Sorry just saw this - I can't remember. I know I have had watches stop due to deflection when testing, but I can't recall if it was one of these or not.

Cheers, Al